ANALISA PERUBAHAN SIFAT MEKANIK DAN STRUKTUR MIKRO MULTI QUENCHING TERHADAP HASIL PACK CARBURIZING BAJA KARBON RENDAH

 Baja karbon yang mengandung unsur karbon yang rendah akan mempunyai sifat yang kekerasan dan kekuatan tariknya rendah, ductile ini akan memudahkan dibentuk dibanding baja paduan atau baja karbon tinggi. Disisi lain harganyapun relatif murah sehingga menjadikan bahan ini banyak digunakan sebagai bahan dasar untuk pembuatan suatu produk. Untuk meningkatkan sifat yang kuat dan keras pada permukaannya, material ini dapat dilakukan proses perlakuan panas thermoikimia melalui penambahan kadar karbon pada permukaannya, sehingga produk tersebut dapat difungsikan sesuai dengan  fungsi desainnya. Salah satu cara yang dapat dilakukan untuk meningkatkan kekerasan permukaan baja karbon rendah yaitu dilakukan proses pack carburizing. Proses carburizing ini, dilakukan pada sebuah tungku pemanas listrik khusus perlakuan panas yang  mudah dioperasikan dalam pengaturan suhu pemanasan, kecepatan pemanasan dan pengaturan waktu tahan. Pada penelitian ini  dirancang dan dilakukan pada baja rabon rendah mengunakan media karburisasi dengan pebandingan 70% arang aktif dan 30%, kalsium karbonat (CaCO3) pada temperatur   pemanasan 925oC ,  variasi waktu tahan 2, 3 dan 4 jam, kemudian dilanjukan dengan variasi metode quenching (direct quenching, single quenching dan double quencing). Dari ketiga metode quenching dengan variasi holding time pada penelitian ini diperoleh peningkatan kekerasan yang tertinggi yaitu pada metode doubel quenching dengan holding time 3 jam yaitu 94,8 HRBdan nilai impact 0,14 J/mm2. Jika dilihat kekerasan dan ketangguhan yang baik yaitu terjadi pada double quenching dengan holding time 2 jam (kekerasan 94,4 HRB dengan nilai impact rata rata 0,86 J/mm2).

Pengaruh Fraksi Volume dan Orientasi Serat Pada Komposit Hibrid Berpenguat Serat Gambas serta Eceng Gondok Terhadap Kekuatan Bending

Wood is increasingly difficult to obtain due to the use of excess wood. Many efforts were made to replace wood, one of which was composite material. This study aims to determine the most optimal bending strength with the influence of variations in volume fractions and fiber orientation in hybrid composites with luffa fibers and hyacinth fibers. In making composites using the hand lay-up method with alaklization treatment on gambas and hyacinth fibers using 5% NaOH which is varied with the volume fraction used in this study with the ratio of resin: hyacinth: gambas is (60%:20% :20%),(70%:15%:15%), as well as (80% :10%:10%) and the orientation of the fibers with the arrangement of the luffa / hyacinth / luffa layer is (0°/ 45 °/ 90°),  (0˚/45˚/0˚), (90˚/0˚/90˚). Bending testing was performed with ASTM D790 standard and hypothesis testing using the two-way ANOVA method. From the results of bending testing, the most optimal strength value was found, which was 43.33 N / mm2, where the value was not higher than the bending strength value in the multiplex, which was 17.53 N / mm2. Meanwhile, the results of hypothesis testing are that there is an influence on the volume fraction factor, the direction of fiber orientation and the interaction with bending forces

Fenomena Insecurity di Kalangan Remaja dan Hubungannya dengan Pemahaman Aqidah Islam

Penelitian ini bertujuan untuk mengetahui tingkat pemahaman Aqidah Islam pada remaja, mengetahui tingkat insecurity pada remaja, dan menguji apakah terdapat hubungan antara pemahaman Aqidah Islam (X) dengan insecurity (Y) pada remaja. Hipotesis yang diajukan pada penelitian ini adalah adanya pengaruh yang signifikan antara pemahaman aqidah Islam dengan insecurity pada remaja. Penelitian ini menggunakan metode penelitian kuantitatif deskriptif asosiatif. Partisipan pada penelitian ini adalah 96 orang dari kalangan remaja yang berusia 12—21 tahun. Pengumpulan data menggunakan kuesioner yang menggunakan skala sikap model Likert, dan terdiri atas skala untuk mengukur pemahaman aqidah Islam dan insecurity. Data yang diperoleh kemudian dianalisis secara deskriptif, juga menggunakan analisis korelasi Pearson Product Moment. Hasilnya diketahui bahwa tingkat pemahaman aqidah Islam remaja di sudah sangat baik, sementara tingkat insecurity remaja pada tingkat baik. Kemudian, pada uji korelasi diperoleh nilai r = 0,028 (p = 0,05), sehingga korelasi antara kedua variabel signifikan. Hasil penelitian tersebut menunjukkan bahwa pemahaman aqidah berperan secara signifikan terhadap perasaan insecurity remaja. Pemahaman aqidah dianggap sebagai aspek penting yang mempengaruhi remaja dalam menghadapi masa-masa transisi yang sulit

Current techniques in reprogramming cell potency

The first successful attempt to reprogram somatic cell into embryonic-like stem cell was achieved on 2006. Since then, it had sparked a race against time to bring this wonderful invention from bench to bedside but it is not easily achieved due to severe problems in term of epigenetic and genomic. With each problem arise, new technique and protocol will be constructed to try to overcome it. This review addresses the various techniques made available to create iPSC with problems hogging down the technique

Malware visualizer: A web apps malware family classification with machine learning

Within the past few years, malware has been a serious threat to the security and privacy of all mobile phone users. Due to the popularity of smartphones, primarily Android, this makes them a very viable target for spreading malware. Many solutions in the past have proven to be ineffective and result many false positives. Other than that, most of the solution focuses on the android apk file, instead of visualizing the apk into image-based form. The objective of this project is to build a web apps to classify malware by transforming the apk file into image-based representation. This project uses three classification algorithm which are Random Forest (RF), Support Vector Machine (SVM), and Convolutional Neural Network (CNN). The web apps is developed using Python with help of Streamlit with is a Python library for building datadriven web apps. The dataset contains 25 malware classes ranging from Trojan Horses to Spyware and 1 legitimate application class

Anti-cancer effect of Annona Muricata Linn Leaves Crude Extract (AMCE) on breast cancer cell line

Background: Annona muricata Linn which comes from Annonaceae family possesses many therapeutic benefits as reported in previous studies and to no surprise, it has been used in many cultures to treat various ailments including headaches, insomnia, and rheumatism to even treating cancer. However, Annona muricata Linn obtained from different cultivation area does not necessarily offer the same therapeutic effects towards breast cancer (in regards to its bioactive compound production). In this study, anti-proliferative and anti-cancer effects of Annona muricata crude extract (AMCE) on breast cancer cell lines were evaluated. Methods: A screening of nineteen samples of Annona muricata from different location was determined by MTT assay on breast cancer cell lines (MCF-7, MDA-MB-231, and 4 T1) which revealed a varied potency (IC50) amongst them. Then, based on the IC50 profile from the anti-proliferative assay, further downward assays such as cell cycle analysis, Annexin V/FITC, AO/PI, migration, invasion, and wound healing assay were performed only with the most potent leaf aqueous extract (B1 AMCE) on 4 T1 breast cancer cell line to investigate its anti-cancer effect. Then, the in vivo anti-cancer study was conducted where mice were fed with extract after inducing the tumor. At the end of the experiment, histopathology of tumor section, tumor nitric oxide level, tumor malondialdehyde level, clonogenic assay, T cell immunophenotyping, and proteome profiler analysis were performed. Results: Annona muricata crude extract samples exhibited different level of cytotoxicity toward breast cancer cell lines. The selected B1 AMCE reduced the tumor’s size and weight, showed anti-metastatic features, and induced apoptosis in vitro and in vivo of the 4 T1 cells. Furthermore, it decreased the level of nitric oxide and malondialdehyde in tumor while also increased the level of white blood cell, T-cell, and natural killer cell population. Conclusion: The results suggest that, B1 AMCE is a promising candidate for cancer treatment especially in breast cancer and deserves further research as an alternative to conventional drugs while also stressed out the selection of soursop sample which plays a significant role in determining its potential therapeutic effect on cancer

Comparison of in vivo toxicity, antioxidant and immunomodulatory activities of coconut, nipah and pineapple juice vinegars

Background: Vinegar is widely used as a food additive, in food preparation and as a food supplement. This study compared the phenolic acid profiles and in vivo toxicities, and antioxidant and immunomodulatory effects of coconut, nipah and pineapple juice vinegars, which were respectively prepared via a two-step fermentation using Saccharomyces cerevisiae 7013 INRA and Acetobacter aceti vat Europeans. Results: Pineapple juice vinegar, which had the highest total phenolic acid content, also exhibited the greatest in vitro antioxidant capacity compared to coconut juice and nipah juice vinegars. Following acute and sub-chronic in vivo toxicity evaluation, no toxicity and mortality were evident and there were no significant differences in the serum biochemical profiles between mice administered the vinegars versus the control group. In the sub-chronic toxicity evaluation, the highest liver antioxidant levels were found in mice fed with pineapple juice vinegar, followed by coconut juice and nipah juice vinegars. However, compared to the pineapple juice and nipah juice vinegars, the mice fed with coconut juice vinegar, exhibited a higher population of CD4+ and CD8+ T-lymphocytes in the spleen, which was associated with greater levels of serum interleukin-2 and interferon-γ cytokines. Conclusions: Overall, the data suggested that not all vinegar samples cause acute and sub-chronic toxicity in vivo. Moreover, the in vivo immunity and organ antioxidant levels were enhanced, to varying extents, by the phenolic acids present in the vinegars. The results obtained in this study provide appropriate guidelines for further in vivo bioactivity studies and pre-clinical assessments of vinegar consumption

Apoptosis and metastasis inhibitory potential of pineapple vinegar against mouse mammary gland cells in vitro and in vivo

Background: Plant-based food medicine and functional foods have been consumed extensively due to their bioactive substances and health-beneficial effects. Vinegar is one of them due to its bioactivities, which confers benefits on human body. Our previous study has produced pineapple vinegar that is rich in gallic acid and caffeic acid via 2 steps fermentation. There are many evidences that show the effectiveness of these resources in inhibiting the proliferation and metastasis of the cancer cells through several mechanisms. Methods: Freeze-dried pineapple vinegar was evaluated for its in vitro apoptosis and metastasis inhibitory potential using MTT, cell cycle, Annexin V and scratch assays. The in vivo test using BALB/c mice challenged with 4 T1 cells was further investigated by pre-treating the mice with 0.08 or 2 ml/kg body weight of freshly-prepared pineapple vinegar for 28 days. The tumor weight, apoptotic state of cells in tumor, metastasis and immune response of the untreated and pineapple vinegar treatment group were evaluated and compared. Results: From the in vitro study, an IC50 value of 0.25 mg/mL after 48 h of treatment was established. Annexin V/PI and scratch closure assays showed that pineapple vinegar induced 70% of cell population to undergo apoptosis and inhibited 30% of wound closure of 4 T1 cells. High concentration of pineapple vinegar (2 ml/kg body weight) led to the reduction of tumor weight and volume by 45%as compared to the untreated 4 T1-challenged mice. This effect might have been contributed by the increase of T cell and NK cells population associated with the overexpression of IL-2 andIFN-γ cytokines and splenocyte cytotoxicity. Furthermore, fewer instances of metastasis events were recorded in the pineapple vinegar treatment group and this could be explained by the downregulation of inflammation related genes (iNOS, NF-kB and COX2), metastasis related genes (iCAM, VEGF and MMP9) and angeogenesis related genes (CD26, TIMP1, HGF, MMP3, IGFBP-1 and IGFBP-2). Conclusion: The ability of pineapple vinegar to delay cancer progression portrayed its potential as chemopreventive dietry intervention for cancer therapy

Subchronic toxicity, immunoregulation and anti-breast tumor effect of Nordamnacantal, an anthraquinone extracted from the stems of Morinda citrifolia L.

Background: Morinda citrifolia L. that was reported with immunomodulating and cytotoxic effects has been traditionally used to treat multiple illnesses including cancer. An anthraquinone derived from fruits of Morinda citrifolia L., nordamnacanthal, is a promising agent possessing several in vitro biological activities. However, the in vivo anti-tumor effects and the safety profile of nordamnacanthal are yet to be evaluated. Methods: In vitro cytotoxicity of nordamnacanthal was tested using MTT, cell cycle and Annexin V/PI assays on human MCF-7 and MDA-MB231 breast cancer cells. Mice were orally fed with nordamnacanthal daily for 28 days for oral subchronic toxicity study. Then, the in vivo anti-tumor effect was evaluated on 4T1 murine cancer cells-challenged mice. Changes of tumor size and immune parameters were evaluated on the untreated and nordamnacanthal treated mice. Results: Nordamnacanthal was found to possess cytotoxic effects on MDA-MB231, MCF-7 and 4T1 cells in vitro. Moreover, based on the cell cycle and Annexin V results, nordamnacanthal managed to induce cell death in both MDA-MB231 and MCF-7 cells. Additionally, no mortality, signs of toxicity and changes of serum liver profile were observed in nordamnacanthal treated mice in the subchronic toxicity study. Furthermore, 50 mg/kg body weight of nordamncanthal successfully delayed the progression of 4T1 tumors in Balb/C mice after 28 days of treatment. Treatment with nordamnacanthal was also able to increase tumor immunity as evidenced by the immunophenotyping of the spleen and YAC-1 cytotoxicity assays. Conclusion: Nordamnacanthal managed to inhibit the growth and induce cell death in MDA-MB231 and MCF-7 cell lines in vitro and cease the tumor progression of 4T1 cells in vivo. Overall, nordamnacanthal holds interesting anti-cancer properties that can be further explored

The growth inhibitory potential and antimetastatic effect of camel urine on breast cancer cells in vitro and in vivo

Although it may sound unpleasant, camel urine has been consumed extensively for years in the Middle East as it is believed to be able to treat a wide range of diseases such as fever, cold, or even cancer. People usually take it by mixing small drops with camel milk or take it directly. The project aims to study the effects of camel urine in inhibiting the growth potential and metastatic ability of 4T1 cancer cell line in vitro and in vivo. Based on the MTT result, the cytotoxicity of camel urine against 4T1 cell was established, and it was dose-dependent. Additionally, the antimetastatic potential of camel urine was tested by running several assays such as scratch assay, migration and invasion assay, and mouse aortic ring assay with promising results in the ability of camel urine to inhibit metastatic process of the 4T1 cells. In order to fully establish camel urine’s potential, an in vivo study was carried out by treating mice inoculated with 4T1 cells with 2 different doses of camel urine. By the end of the treatment period, the tumor in both treated groups had reduced in size as compared to the control group. Additional assays such as the TUNEL assay, immunophenotyping, cytokine level detection assay, clonogenic assay, and proteome profiler demonstrated the capability of camel urine to reduce and inhibit the metastatic potential of 4T1 cells in vivo. To sum up, further study of anticancer properties of camel urine is justified, as evidenced through the in vitro and in vivo studies carried out. Better results were obtained at higher concentration of camel urine used in vivo. Apart from that, this project has laid out the mechanisms employed by the substance to inhibit the growth and the metastatic process of the 4T1 cell